FAIR VALUE MEASUREMENTS: Fair Value Carrying Amounts and Estimated Fair Values (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	[1]	$ 3,804	$ 3,804
Long-term debt	[1]	1,726,474	1,615,502
Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	[1]	3,804	3,804
Long-term debt	[1]	1,813,243	1,788,197
Idaho Power Company | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	[1]	1,726,474	1,615,502
Idaho Power Company | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	[1]	$ 1,813,243	$ 1,788,197

[1] Notes receivable and long-term debt are categorized as Level 3 and Level 2, respectively, of the fair value hierarchy, as defined earlier in this Note 16.